Of interest to some. rl
From the New Scientist (there are important diagrams at the site-- <http://www.newscientist.com/article/mg19626303.900;jsessionid=OEGLIBGOIACB > Is mathematical pattern the theory of everything? by Zeeya Merali GARRETT LISI is an unlikely individual to be staking a claim for a theory of everything. He has no university affiliation and spends most of the year surfing in Hawaii. In winter, he heads to the mountains near Lake Tahoe, California, to teach snowboarding. Until recently, physics was not much more than a hobby. That hasn't stopped some leading physicists sitting up and taking notice after Lisi made his theory public on the physics pre-print archive this week (www.arxiv.org/abs/0711.0770). By analysing the most elegant and intricate pattern known to mathematics, Lisi has uncovered a relationship underlying all the universe's particles and forces, including gravity - or so he hopes. Lee Smolin at the Perimeter Institute for Theoretical Physics (PI) in Waterloo, Ontario, Canada, describes Lisi's work as "fabulous". "It is one of the most compelling unification models I've seen in many, many years," he says. That's some achievement, as physicists have been trying to find a uniform framework for the fundamental forces and particles ever since they developed the standard model more than 30 years ago. The standard model successfully weaves together three of the four fundamental forces of nature: the electromagnetic force; the strong force, which binds quarks together in atomic nuclei; and the weak force, which controls radioactive decay. The problem has been that gravity has so far refused to join the party. Most attempts to bring gravity into the picture have been based on string theory, which proposes that particles are ultimately composed of minuscule strings. Lisi has never been a fan of string theory and says that it's because of pressure to step into line that he abandoned academia after his PhD. "I've never been much of a follower, so I walked off to search for my own theory," he says. Last year, he won a research grant from the charitably funded Foundational Questions Institute to pursue his ideas. He had been tinkering with "weird" equations for years and getting nowhere, but six months ago he stumbled on a research paper analysing E8 - a complex, eight-dimensional mathematical pattern with 248 points. He noticed that some of the equations describing its structure matched his own. "The moment this happened my brain exploded with the implications and the beauty of the thing," says Lisi. "I thought: 'Holy crap, that's it!'" What Lisi had realised was that if he could find a way to place the various elementary particles and forces on E8's 248 points, it might explain, for example, how the forces make particles decay, as seen in particle accelerators. Lisi is not the first person to associate particles with the points of symmetric patterns. In the 1950s, Murray Gell-Mann and colleagues correctly predicted the existence of the "omega-minus" particle after mapping known particles onto the points of a symmetrical mathematical structure called SU(3). This exposed a blank slot, where the new particle fitted. Before tackling the daunting E8, Lisi examined a smaller cousin, a hexagonal pattern called G2, to see if it would explain how the strong nuclear force works. According to the standard model, forces are carried by particles: for example, the strong force is carried by gluons. Every quark has a quantum property called its "colour charge" - red, green or blue - which denotes how the quarks are affected by gluons. Lisi labelled points on G2 with quarks and anti-quarks of each colour, and with various gluons, and found that he could reproduce the way that quarks are known to change colour when they interact with gluons, using nothing more than high-school geometry (see Graphic). Turning to the geometry of the next simplest pattern in the family, Lisi found he was able to explain the interactions between neutrinos and electrons by using the star-like F4. The standard model already successfully describes the electroweak force, uniting the electromagnetic and the weak forces. Lisi added gravity into the mix by including two force-carrying particles called "e-phi" and "omega", to the F4 diagram - creating a "gravi-electroweak" force. [snip] ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
